I get a discount with Progressive. In fact, they lowered my MC rate when I added my boat to the policy. I've found that if you call them, as opposed to doing it online, you can get the negotiate a bit. I have two bikes (DRZ400 and Nighthawk 750) with full coverage for $190 a year.

My experience calling Progressive matches yours. Friends (all in WA state) told me stories of how adding a 3rd bike cost almost zero but when I called (I had three bikes at the time and am in OR) there was no such discount for the third bike. Each bike was maybe 5% cheaper than I was paying with State Farm but the guy on the phone was beyond oily.

Also, there is no substitute for calling around. Insurance varies massively by state and personal circumstances (crime rate where you live, age, driving history, marital status, credit score etc etc) that asking for data from others on the net is pretty pointless.